A New Variant of the Claisen Rearrangement from Malonate-Derived Allylic Trimethylsilyl Ketene Acetals: Efficient, Highly Enantio- and Diastereoselective Syntheses of (+)-Methyl Dihydroepijasmonate and (+)-Methyl Epijasmonate
作者:Charles Fehr、José Galindo
DOI:10.1002/(sici)1521-3773(20000204)39:3<569::aid-anie569>3.0.co;2-8
日期:2000.2.4
Complete chirality transfer occurs in the smooth Claisen rearrangement of the trimethylsilyl (TMS) ketene acetals, which were prepared from allylic malonates (R)-1 (R=pentyl, 2-(Z)-pentenyl). These are in turn accessible by enantioselective reduction/esterification or by enzymatic kinetic resolution. The cis configuration in (+)-3 was achieved by highly syn-selective epoxidation of (+)-2, followed
完全手性转移发生在由烯丙基丙二酸酯(R)-1(R =戊基,2-(Z)-戊烯基)制得的三甲基甲硅烷基(TMS)乙烯酮缩醛的平滑克莱森重排中。这些反过来可通过对映选择性还原/酯化或酶动力学拆分来获得。(+)-3中的顺式构型是通过(+)-2的高度同位选择性环氧化实现的,然后进行表面上的1,2-H迁移。